Add include.

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_api_message.h"
 #include "vm/dart_api_state.h"
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/debuginfo.h"
 #include "vm/exceptions.h"
 #include "vm/flags.h"
 #include "vm/growable_array.h"
 #include "vm/lockers.h"
 #include "vm/message.h"
 #include "vm/message_handler.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
+#include "vm/os_thread.h"
 #include "vm/port.h"
 #include "vm/profiler.h"
 #include "vm/resolver.h"
 #include "vm/reusable_handles.h"
 #include "vm/service.h"
 #include "vm/stack_frame.h"
 #include "vm/symbols.h"
 #include "vm/tags.h"
 #include "vm/timer.h"
 #include "vm/unicode.h"
@@ skipping 5386 matching lines @@
 
 
 DART_EXPORT void Dart_RegisterRootServiceRequestCallback(
     const char* name,
     Dart_ServiceRequestCallback callback,
     void* user_data) {
   Service::RegisterRootEmbedderCallback(name, callback, user_data);
 }
 
 }  // namespace dart